9) Non-compatible models:
Living next-door to the type family are several other models in various stages of development.
The Enneagram does have themes, parts and processes in a greater or lesser extent, but people who espouse the Enneagram cannot seem to decide what it is modeling. (Virtues and vices? Personalities? Emotions? etc.) If it turns out to be about virtues and emotions, then it may add to type. The Enneagram’s triangular nature may also spark ideas about personal development.
The 5-Factor model is an attempt to capture in 1 model the qualities of numerous other models: Essential Motivators, type, functions, development, emotional state all in one. However, the 5-Factor model cannot be used in all the ways the multiple models of type are used, because by trying to be a more universal model, it loses the quality of having different perspectives and having different kinds of models (themes, processes, parts, wholes, etc.) Usefulness is lost.